WASHINGTON — The vast majority of terror attacks in France were carried out by Islamic radicals who had been known to police or intelligence services, according to a new report by a global security think tank.

Bratislava-based GLOBSEC examined 22 terror incidents in France since 2012. Nearly 80 percent of the people behind those attacks had been on a terror watchlist, and 97 percent had been on the radar of authorities, according to the firm's new analysis, obtained by NBC News.

The figures included Saïd and Chérif Kouachi, career criminals with long records who killed 12 people in January 2015 in the offices of the satirical weekly newspaper Charlie Hebdo in Paris.

The statistics are likely to bolster the longstanding criticism leveled at France and other European countries that authorities are not doing enough to prosecute and imprison those who pose a threat. Statutes related to providing material support to terrorists, which carry long prison terms in the U.S., are not often prosecuted in France, and jail sentences are much shorter.

"The main issue throughout Europe is the sentencing, which is extremely lenient and also allows for terrorists/jihadists to be freed quite early for 'good behavior,'" said London-based terror expert Olivier Guitta, founder and managing director of the security firm GlobalStrat.

Of 78 people suspected of carrying out the attacks, 49 percent had previous criminal convictions, including 19 percent who were repeat offenders, the report said.

Authorities work at a makeshift emergency services base after a deadly shooting in Strasbourg, France, early on Dec. 12, 2018.Patrick Seeger

That included Cherif Chekatt, killed last month after he opened fire on a Christmas market in Strasbourg.

The report urges France to deport foreigners who are convicted of terrorism-related offenses, noting that 15 percent of those on France's terror watchlist are foreigners.